1. Acronym of the phrase "Shut the fuck up" which is commonly used amongst teenagers and on MSN

2. Acronym of the phrase "Squad the fuck up". It is used the Battlefield game series (Battlefield 1943, Battlefield 2, Battlefield 2142) and is used when one believes there is lack of teamwork when there are no squads. By saying this, people will make squads and improve the teamwork, therefore, making a better chance of winning.